The invention relates to an open end spinning machine which includes an apparatus for re-attaching a thread which had previously been held in a clamping fixture and which had been severed at equal, predetermined distances from the fiber collection groove of the spinning rotor. The spinning machine further includes thread drawoff tubes through which air may enter the spinning rotors.
In a known machine of this type, the fixtures which clamp and sever the threads are so disposed that the clamping and severing operation takes place within the thread drawoff tubes, i.e. it takes place in relatively close proximity to the fiber collection groove of the spinning rotor. The thread drawoff mechanism must be stopped very rapidly and abruptly in order that a thread, whose breakage is sensed by a sensor also located in close proximity to the clamping and severing fixture, is stopped while it is still in the effective operating region of the clamping and severing fixture. Since the thread drawoff tube is usually fastened in or on a movable cover of the spinning rotor housing, the clamping and severing fixture and the sensor must also be mounted on this movable cover and this requires expensive clutches and connections for providing drive power from the spinning machine.
DT-PS No. 1,289,472 has disclosed a clamping device disposed outside of the thread drawoff tube and this device is capable of clamping a thread whose broken end still lies within the tube and the thread may be guided back into the fiber collection groove for re-attachment after being unclamped. However, this re-attachment attempt may fail because the uncut ends of the threads are unequal in length, shape and the same. At the restarting of such open end spinning machine therefore there is a risk that many threads are not re-attaching to the unspun fibers in the spinning rotors.